The drain clean is a small capped pipeline sticking out above the ground. Sadly, finding it is not always straightforward.
https://simonyyzi581.edublogs.org/2023/05/23/14-businesses-doing-a-great-job-at-%ce%b1%cf%80%ce%bf%cf%86%cf%81%ce%b1%ce%be%ce%b5%ce%b9%cf%83-%cf%87%ce%b1%ce%bb%ce%b1%ce%bd%ce%b4%cf%81%ce%b9-%ce%ba%ce%bf%cf%83%cf%84%ce%bf%cf%83/